Fuel control foe fluid fuel buhners



Feb. 23, 1943. A. N. SCHREUDER 22,276

I GONTROL FOR FLUID FUEL BURNER Original Filed Jul .14, 1958 FUEL 3 Shasta-Sheet l Feb. 23, 1943. A. N. SCHREUDER FUEL downion FOR FLUID FUEL BURNERS ori inal Filed Ju1 14, 19:58]

'5 Sheets-Sheet 2 W W 2 m2 2 2 D no VOLT M E W 2W Feb. 23, 1943. A. N. SCHREUDE'R 5 FUEL QQNTROL FOR FLUID FUEL BURNERS Original Filed July 14, 1938 3 Sheets-Shut 3 Reissued Feb. 23, 1943 Re. I 22,276

- um'rso STATES PATENT OFFICE.

I romlcou'rnor. roi fzilm roan nUnNElt Q I Arthur H. Schreuder, Chicago, 111., assignor to Quaker Manufacturing Company, Chicago, Iil., a corporation of Illinois Original No. 2,231,041, dated April 1, 1941, serial No. 219,269, m 14.

issue lanuary 23, 1942 18 Claims.

My invention relates to an improvement in control means for burners and is herein shown as'applied to .liquid hydrocarbon burners oi! a well known type.

One purpose is the provision of means for increasing and reducing air pressure in a hydrocarbon burner independently of fan .or motor speed. I

Another purpose is the provision of safety means ior cutting of! the iuelieed to such a burner when the tan or motor circuit is broken or the tan ceases to operate.

Another purpose is the provision of improved switch means for controlling the operation of such a burner.

Another purpose is the provision or improved means for controlling the delivery of liquid iuel to such a burner.

Another purpose is the provision of means for employing an air pressure responsive element to control the operation of a liquid hydrocarbon burner.

Other purposes will appear from. time to time during the course oi the'specification and claims.

I illustrate my invention more or less diagramriixilaticaliy in the accompanying drawings where- Figure 1 is a front elevation;

1938. Application for re- Serial No. 427,968

ci. ass-1) vention. "It will v the line zsrin vaporized hydrocarbon is mixed with the air flowing in through the a i and is thereafter burned. 8 indicates a baiiie located beneath v the pot and herein shown as centrally apertured as at 9, the air supply being delivered through the aperture 9, as will later appear. in indicates a pilot ring. 4

ii diagrammatically illustrates any suitable valve member or mechanism, the details or which the present indo not of themselves form. part of be understood that it includes a hydrocarbon iuel. It will be minimum setting sunlcient fuel is supplied along 8 tovmaintain combustion at a low or pilot stage. At that time the pilot ring Ill is efiective. For the intermediate and high fires. the air-admitted through the apertures 5 below the as primary air which, when rises aperture of the pilot ring mixed through the central l0 and is burned upon air flowing through the holes ii above the pilot As indicating three-stage flow,

practical means of providing this I illustrate in the wiring diatwo oil valve members I! and Figure 2 is a section on the line 2-2 of Fig- I: when one of these valves is in closed posir 2 tion and one open, an intermediate supply is de- Figure 3 is a fragmentary view of a portion of liveredziwhen both are in open-position, a maxithe structure shown in Figurw 1 and 2; 11mm supply is delivered. It will be understood Figure 4 is a section on the line 4-4 of Fig that when both valves are closed, appropriate li means are provided, by by-pass or otherwise, for Figure 5 is a view similar to Figure 4 with the maintaining the above mentioned minimum fuel parts in a diflerent position; 1 supply;

able base or support upon whichis mounted a 1 stove or furnace shell generally indicated at 2.

Within said shell, the details of which form no 5 8, which air supply passes upwardly throush the part of the present invention, is located an inaperture! to the space betweenthe shell 3 and her heater drum i. Mounted within the drum is f the pot l. a v

a pot l having a plurality of air inlet apertures In order to vary the pressurewithin the chams through which air is supplied tor mixture withher A'and thus to vary the air delivery to-the in the pot with liquid hydrocarbon supplied along burner, I provide an ad tional air portincluding the line B. It will be observed from Figure 2 that a pass ge housing generally indicated as i6. ii

the liquid hydrocarbon is deliv red to the congenerally closed, the motor within the housing 45 is effective to rotate the in and to cause a air to enter the chamber A beneath the partition indicates any suitable connection between it and cave bottom I 0! the pot 4' and it will be under the chamber A. Pivoted in the opening ll of the stood that the hydrocarbon is vaporized by the giassat g; housgig is a shutter or gate generally inea c a 88 heat of combustion in or above the pot and the which is providedwith ears 20 mixture with the second-' erally cylindrical or circular .minates in a generally radial extension 23 to contact 35 adapted to be opposed to line 13, which extends 33b to scribed connections. -yond the heater II to the secondary coil 33 of the transformer C where it may join the line 34 1 at which rest in slot 2| which serve as pivots. 32

indicates any suitable weight or weights tending the weight 22. The position in which it is shown in Figure 4 is an example of a satisfactory maximum opening position.

.23 indicates a bracket in the end of which --is adjustably mounted the screw 24 the head 2 of which serves as an abutment the purpose of which will later appear.

26 is an additional housing mounted on the side of the passage housing ll. 21 is a bracket. secured to the housing 23, to which bracket is secured the bimetallic loop 23 shown as genin form. It terwhich is secured an insulating bar 33. Mounted on said baris a contact 3| having a conductive connection 32. Additionally mounted on it is a flexible leaf 33 of conductive material in circuit with the line 34. The leaf 33 is provided with a the contact 3|, and which is in line to be engaged by the head 25 of the screw 24 in such fashion that a rotation in a clockwise direction of the shutter or gate I! causes a closure of a circuit, which causes a conductive contact between the mem-' bers 3| and 35 and thus puts the line 33 and 33 in circuit. Located within the loop or interior of the bimetallic member 23 is a resistant heating element or coil 38 having conductors 31, 38.

It will be understood that when the heater 3! fer-ring to the position of the parts in Figure 4. This movement of the insulating bar 3|) can be adjustably limited by the employment of the screw stop 39 adjustable in any suitable abutment 40. Preferably the parts are'so adjusted that the member 30 cannot be flexed sufilciently to the'right to permit a contact between the members 3| and "to be broken when the gate is in the closed position in which it is shown in Figure 5.

Referring to the wiring diagram of Figure 6, 4| generally indicates a room thermostat structure having a contact strip 42, the. posltion'of which may be controlled in response to variations in room temperature, as by the bimetallic coil 43. II is the main with the main line conductor II which extends to the secondary coil ll of the transformer C. 41 is an intermediate contact in circuit with the to the heating coil II. which surrounds or affects a bimetallic strip 50 which controls any suitable valve plunger'll already referred to. The line continues as at 430 to the line 32 of the contact 3| on the insulating Extending from the line II is a shunt ithe heating coil II, which controls the bimetallic strip 32 which actuates a the bimetallic loop 28 (Figs. 4 and 5). The line 33 extends beyond the coil 36 to an additional heating coil II and extends therebeyond through line 33a and line 32 to the contact 3|. The coil 3| controls a bimetallic strip 62 which controls the second 011 valve l3 already mentioned. The primary coil in of the transformer C nected across the lines 54, 55 in parallel with the motor.

It will be understood that the heater above described may be run at three stages. First, a pilot stage in which a minimum oil supply is supplied and the oil valves I2 and |3are both closed. At

this stage the fan is inactive and the weights 2! will hold the shutter i! in the open position in which it ,is shown in Figure 4, and the burner will run at natural draft. The bulk of the air supply will flow through the inlet II, but some may flow through the fan. In any event, there is -no forced draft and preferably only suillcient combustion is maintained to provide a pilot for intermediate or full combustion. g

If an intermediate fire is desired, or if the device is operated by the room thermostat, the leaf 3! bridges the contacts N, 41. In the form herein shown, as in Figure 6, this bridging or circuitclosing takes place in response to the closed switch 53, which controls actuating circuit I, II

for the motor I, which lines extend to'any suitable source of electric power as at D.

If desired, a manually controllable switch 33 may be in circuit to break all of the above de- The line b extends bea common terminal. ll is'an additional contact on the thermostat II from which leads the line 3! which extends to the heating coil 33 for ilexure of the member 43 as the room ture drops. The initial result of the closure is as follows. Current flows through the coil II and flexes the leaf 52. This closes the switch 53, which closes the motor circuit and causes the motor and fan to operate. The motor operation causes a delivery of air into the space A and upwardly about the pot 4. This air reaches the interior of the pot through the apertures 5, giving an increased air supply. At the same time, the baflle 35 in the housing I6 is effective to direct a blast or current of air against the lower half of the shutter ID. This closes or tends to close the shutter against the gravital action of the weights 22. As the shutter closes. the contact 25 on the shutter engages the flexible leaf 33 and closes the contacts 3|, 35. This closes the circuit through the heater 4! and by flexing upwardly the bimetallic strip 53 raises the oil valve l2 and admits an additional supply of oil to the bottom of the pot 4. The member 30 acts as a stop and prevents a complete closure of the shutter It, so some of the air pressure is relieved through 'the aperture I 8 and the full effect of the fan is. therefore, not felt in the pot 4. In other words an intermediate rather than a full supply ofair is delivered to the pot l to burn the intermediate supply of oil which is admitted y lifting the valve l2, the valve I3 being still An additional drop of the room temperature.

or a manual closure, closes a further circuit be-' tween the contacts 44 and 3|). O'ne eifect of this additional closure is to heat the resistance 38 and to cause the insulating bar 30 to move to the right as shown in Figure 4, in response to the flexure of the bimetallic loop 28. Continued air" pressure within the chamber A and the housing i6 causes the shutter Is to follow the bar 33 as it recedes, keeping the switch contacts 3| and 3! closed. The parts are preferably so set that the shutter I9 is substantially completely closed, as shown 'in Figure 5,'thus' preventing air pressure within the, space A and about the pot 4. As above mentioned. -the stop 3! is so set as to prevent such a further recession of the member 30 as would break the contact between is contemperathe members 3| and 35. A furmaximum supply' is-a reversal of the above deenergization of thee ,same time, the

air pressure or air supply,

- 'ilre and that either manuallyfor the the contact-betweenthe v and the valve drops to the fully butthe valve l2 time lag require bottom of vice, neverthless many size, shape of parts without departing.

1 operation at electrically connected by -motor and the diagram of Figure 6 ther result of a. bridging oi. the contacts M and II is the heatingioi the coil II. which causes a nexure'ot the strip '2, which in turn lifts the maximum oil supply valve it. Thus a full maximum supply of oil is. provided, and since any eiiective escapefof air through the aperture II is prevented the air pressure correspondingly steppedup, a maximum supply of air being provided for the combustionoi' the 1 of oil. y

when a-change is made from maximum-combustion to intermediate combustion and from intermediate combustion to pilot combustion, there described action; Asi response to thermostatic control operation the contact is broken cts N and I, the resultis a oils 3. and", without affecting, however, the motor circuit. Asthe coil "cools; the barilirtakes a counter-clockwise movement, re tially opens the shutter ll and-permits a reduction' of air pressure-within'-the space' A andthus a3reduction'='-o! air supply to. the pot 4. At .the oil valve"-il.is closedand the device is restored to intermediate operation. It will be noted that sume that or to manual between" the cents as the oil supply passes from-intermediate to maximum,; or drops-from maximum to intermediate, is obtained without" aflectingthe operation of the fan or motor at all. Assuming that -the device is'onintermediate membersJl-andfl isbroken, this causes a de-energization of the re- 'sistance 5i which permits a breaking of the motor circuit-switch "51;" It also causes adeenergizationof the coil which controls the valve l2. "The motor, therefore, stops running 12 closes, and -the shutter ll open position inwhich it is shownin Figure 4. immediately upon-tha-opening oi theswitch I is closed more slowly-due to the dfor the cooling of bi-metallic member 50. Any temporary excess supply'ot oil is amply taken careor under the natural draft condition, as sufilcient air is admitted through the aperture ll to prevent any carbon deposit or any sooting up of the burner." "I'his is possible because-the maximum oil valve -llhas already been closed and the drop from the intermediate oil supply to minimum oil-supply does not cause any carbondeposit and does no admit into the I the pot l any more oil than can readily be bumed'otl-by a natural'drait. ,3 It-wlli be realized that whereas I have described andshown a practical and operative-dechanges may be made in number, disposition and relationship from-the spirit of my invention. For example, as shown in Figure 7. imay employ a circuit in which the tan isin all stages of combustion-- from the. pilot stage .up. V

- As illustrated in the diagram the motor! is lines "a and a to the service lines 4 and 85, respectively. Both the transformer C are manually conwitch it. The electrical connections are identical with thosein the electrical and are indicated by like ption that the line no, associated bimetallic trolled by the s the heating coil Di, and the strip 52 and motor switch it are-omitted. it'will 15 some and air deliveryare whole operating circuit in the increase and reduction of rm'ostaticalh used in connection 7 sion 13111113901 unit,

*-The motor circuit cuts'out actuating circuit for sai maintain at least a be realized that in the sumes the intermediate position above described with the contacts ii -and I! closed. when the room thermostatiunctions and closes the .con-

tacts and I1, the heater coil ll is energized and opens. the valve II tor an intermediate fire. However, the shutter remainxin. intermediate position. f

:It will be observed in both forms that the switch structure, including the contacts Ii. and .il, serves as a safety device which cuts out the the event that-the motor circuit is broken or the fan ceases to operate. It is necessary for. the fan to be in operation. in order to maintain the contacts ll and contact, as otherwise the weights I! pull the shutter into fully open position, and permit .the lea'i ll to flex into circuit breaking condition. This provides a positive safety device which makes it impossible for anything more than a can be burned oil by natural drait and will pilot name in both forms or the device without causing sooting up or carbon deposit. In'no event can an excess supply oi oil flow into the pot l, a supply too great for the available air to burn it off. This prevents flooding oi the pot and escape of excess oil from the burner,. with the consequent fire hazard -.which is present in so many prior art burners.

It will be understood that whereas I have shown my invention as applied-to, afurnace unit, it may beemployed in connection with anyduct with any furnace or burner, and may -forexampl or in a burner completely housed outside of a heating plant. Also, it will be understood .that I mayemploy a wide variety of switch mechanisms in the place of those shown, and may for example employ a mercury tube switch. I

I claim: a

1. In combination, aburner, passage means for delivering a fluid fuel to said burner, means 'for delivering air under pressure to said burner, a motor for actuating said air delivery means, an d motor. an air admission member adapted to admit air under naturaldrait to the burner-when said air delivery means isnot operating, and adapted to permit the escape by to reduce ting the position ior delivering --livered to the burner,

oi a portion'oi. the air under pressure; and therethe pressure of the air delivered to the burner. when said air delivery means is operating. shutter means for said air admission memher. and temperature-controlled means for setlcontrolling the to shutter will be closed and the fuel flow increased as the temperature falls 2. In combination, a for delivering a fluid fuel to said burner, means air under pressure to said burner. a motor for actuating said air delivery means, an actuating circuit i'or sion member adapted to admit'air under natural draft to the burner when said air delivery means is not operating, and adapted to permit the escape of a. portion of the air-under pressure, and thereby to reduce the pressure of the air dewhen means. is operating. shutter means for said air admissionmember, responsive'----to air pressure created by the air. delivery means, and means for ilrst or pilot stage. the shutter II, with the the motor in operation, as;

e be employed in a converof said shutter means-and el delivery means so that the burner, passage means said motor, an air admissaid air delivery motor,

- flow to intermediate controlling the fuel delivery means in response to movement of said shutter means, including a switch having a pair of normally separated contacts, and means for closing said contacts in response to movement of said shutter means.

3. In combination, a burner, passage means for delivering a fluid fuel to said burner, means for controlling the flow of fuel through said passage means in a plurality of stages, including a minimum flow, an intermediate 'flow, and a maximum flow, means for delivering air under pressure to said burner; a motor for actuating said air delivery means, an actuating circuit for said an additional air port adapted toadmit air under natural draft to the burner, when said motor drlvenair delivery means is not operating, and adapted to permit the escape of air under pressure, the air delivered to the burner, when the motor driven air delivery means is operating, normally open shutter means for said additional shutter meansbeing movable toward closed position by airpressure created by the said air delivery means,,a multiple contact room thermostat including a temperature responsive member, a pair of contacts adapted for initial closure thereby, and an additional contact adapted for subsequent closure, a control circuit including said initial two contacts, means for closing the motor circuit in response to closure of said control circuit, means in said control circuit adapt edto increase the flow of fuel-from minimum fiow, an additional circuit port, Said.

said third contact, means in said additional circuit effective when said circuit is closed to increase the flow of fuel from intermediate flow to maximum flow, other means in said last circuit for moving the stop means to permit further closing movement of the shutter and means responsive to an opening movement of said shutter for reducing the flow of fuel when the motor driven air delivery means is not operating.

5. In combination, a burner, means for supplying a fluid fuel to the burner including a valve for adjusting the rate of fuel supply, means including a blower for supplying combustionair to the burner, an auxiliary air port communicating with the burner for admitting air under natural draft when the blower is not operating and permitting the escape of a portion of the and thereby to reduce the pressure of a including said third contact, means in said additional circuit effective when said circuit is closed to increase the flow of fuel from intermediate flow to maximumflow, limit means for said shut ter adapted to prevent its complete closure when the circuit including the initial two contacts is closed, and means responsive to the closure of the additional circuit including the third contact, effective to move said limit means and to permit a further closing movement of said shutter, and thereby to increase the air pressure adjacent the burner chamber.

4. In combination, for delivering a, fluid for, controlling the a burner, passage means fuel to said burner, means flow of fuel through said passage means in a plurality of stages including a minimum flow, an intermediate-flow, and a maximum flow, means for delivering air-under pressure to said burner, a motor for actuating said air delivery means, an actuating circuit for said motor, an additional air port adapted to admit. air .under natural draft to the burner, when said motor driven air delivery means is not operating, and adapted to permit the escape of air under pressure, the pressure of the air delivered to the burner, when the motor driven air delivery means is operating, normally open shutter means for said "additional port, said, shutter means being movabletoward closed position by ,air pressure created by the air delivery means, stop means for limiting this closing movement of the shut 3 ter, a multiple contact room thermostat including'a temperature responsive'member, a pair of contacts adapted for initial closure thereby, and an additional contact adapted for subsequent closure, a control circuit including said; initial two contacts, means for closing the motor circult in response to closure of said contact circuit, means in said control circuit-adapted to increase the flow of fuel from minimum flow to intermediate flow, an additional circuit including ving a fluid fuel to 3 natural draft when air under pressure from the blower when the blower is operating, movable damper means associated with said port for controlling the supply of air to the burner, and means for'simultaneously adjusting the fuel valve and the position v of the damper-means.

6. In combination, a burner, meansior supplythe burner including a valve for adjusting the rate of fuel supply means including a blower for supplying combustion air to the burner, an auxiliary air port communicating with the burner foradmitting air under the blower is not operating escape of a portion of the from the blower when the and permitting the air under pressure blower is operating, sociated with said port for controlling the supply of air to the burner, and temperaturemontrolled means for simultaneously adjusting the fuelvalve and the positioniof the damper means.

7. In combination, a burner, means for supplying a fluid fuel to the burner including a valve and thereby to reduce for adjusting the rate] of fuel supply, means including a blower for 'supplying combustion-air to the burner, an auxiliary air port communi eating with the burner for admitting air under natural draft when and permitting the escape of a portion of the air under pressure from the blower when the blower is operating, a seli-openingshutter for said port, and temperature-controlled means for simultaneously and progressively opening the fuel valve'and closing said shutter.

8. In combination, a burner, means for supplying a. fluid fuel to the burner including a.

valve for adlustingthe rate of fuel supply, means including a blower for supplying combustion air tovthe burner, an auxiliary air port communieating with the burner for admitting air under natural draft when the blower is not operating and permitting the escape of a portion of the air under pressure from the blower when the blower is operating, a self-opening shutter for said port, said shutter being closed by air under pressure from the blower, and temperature-controlled means for simultaneously limiting the closing movement of the shutter and proportionately opening the fuel-valve,

9. In combination, a burner, means for tie livering a fluid fuel to the burner, valve means controlling the flow of fuel to the burner, means including a blower for delivering air under pressure-to the burner means including a passage for either admitting air under natural-draftto the burner or functioning to permit the escape of a portion of the air under pressure from the blower, normally open damper-means for opening or closing said passage, and means effective movable damper means as-' the blower is not operating trolling the flow of tially simultaneously adjusting said valve-means to increase the fuel flow and adjusting said damper-means toward closed position to increase the air supply to the burner.

10. In combination, a burner, means for delivering a fluid fuel to the burner, valve-means controlling the flow of fuel to the burner, means including a blower for delivering air under pressure to the burner, means including a passage for either admitting air under natural-draft to the burner or functioning to permit the escape of a portion of the air under pressure from the blower, normally open damper-means for opening or closing said passage, controlled means for substantially simultaneously adjusting said valve-means to increase the fuel flow and adjusting said damper-means toward closed position to increase the air supp y to the burner.

11. In combination, a burner, means for delivering a fluid fuel to the burner, valve-means concluding a blower for deliveringair under pressure to the burner, means including a passage for either admitting air under natural-draft to the burner or functioning to permit the escape of a portion of the air under pressure from the blower, a normally open damper-means for opening or closing said passage, and means for substantially simultaneously adjusting said valve-means toward or from a fully open position and adjusting said damper-means toward or from a fully closed position to proportionately increase or decrease the flow of fuel and air to the burner.

12. In combination, a burner, means for delivering a fluid fuel to the burner, valve-meanscontrolling the flow of fuel to the burner, means in eluding a blower for delivering air under pressure to the burner, means including a passage for admitting air under also functioning to permit the escape of air under pressure from the blower, normally open dampermeans for opening or closing said passage, means for substantially simultaneously adjusting said valve-means to increase the fuel flow and adjusting said damper-means toward closed position to increase the air supply to the burner, and means for permitting opening movement of the valvemeans only when the blower is functioning.

13. In combination, a burner, means for delivering a fluid fuel to the burner, valve-means controlling the flow of fuel to the burner, means including a blower for delivering air under pressure to the burner, means including a passage for admitting air under natural-draft to the burner and also functioning to permit the escape of air under pressure from the blower, normally open dampermeans for opening or closing said passage, means for substantially simultaneously adjusting said valve-means to increase the fuel flow and adjusting said damper-means toward closed position to increase the air supply to the burner, and meansfor causing the valve-means to reduce the fuel flow to a minimum when the blower ceases to function.

14. In combination, a burner, a chamber supplying air to the burner, means includin a pasand temperaturefuel to the burner, means inonly while the blower is operating for substannatural-draft to the burner and sage for delivering a fluid fuel to said burner, valve means for controlling the flow of fuel through the passage, means for supplying air under super-atmospheric pressure to the chamber, an air duct communicating with the chamber, a shutter in said duct, means for normally moving the shutter to open position to admit air through the duct to the chamber under atmospheric pressure, said shutter being closed by a superatmospheric pressure in the chamber, and means actuated by the closing movement of the shutter for increasing the opening of the fuel valve means.

15. In combination, a burner, a chamber supplying air to the burner, means including a passage for delivering a fluid fuel to said burner, valve means for controlling the flow of fuel through the passage, means including a motordriven fan forsupplying air under super-atmos pheric pressure to the chamber, an air duct communicating with the chamber, a shutter in said duct adapted to be closed'by the pressure in the chamber when the fan is operating, means for normally moving the shutter to open position to admit air to the chamber undernatural draft when the fan is not operating, and means actuated by a closing movement of the shutter for increasing the opening of the fuel .valve means.

16. In combination with a fluid-fuel burner, means for supplying fuel to the burner including a valve for controlling the rate of fuel supply to the burner, a blower adapted to provide a substantially constantoutput of air under pressure and means for selectively directing a portion of this output tothe burner'for combustion air and venting the remainder of the blower output, said venting means also being effective to admit air to the burner under natural draft when the blower is not operating so that the rate of supply of combustion air can be varied from natural draft up to the full output of the blower. 17. In combination a fluid-fuel burner having a plurality of operating stages, means for supplying fuel to the burner including a valve for controlling the rate of fuel supplied, a blower adapted to provide a substantially constant output of air under pressure, and means for directing a portion of this output to the burner for combustion air during one operating stage of the burner and including means for venting the remainder of the blower output, said venting meansalso being effective during another operating stage of the burner to admit combustion air thereto under natural draft when the blower is not operating. 18. In combination with a fluid-fuel burner having a plurality of operating stages, means for and permitting the escape of a portion of said air under pressure when said blower is operating during another operating stage of the burner.

ARTHUR N. SCHREUDER.

blower for delivering a, main supply of 

